Casing patches have long been used in the hydrocarbon recovery industry in conjunction with a repair to a tubing or casing segment in a wellbore. It will be understood that the term “casing patch” as used herein is intended to relate to both patches actually in the casing of a wellbore and patches that are in a tubing string for a wellbore.
It is to be assumed for purposes of this disclosure that a faulty section of casing or tubing has already been cut out of the well and the “stub”, i.e., the piece left downhole, and to which the casing patch will be connected, has been dressed.
Prior art casing patches have included Chevron seals and lead based seals but these have drawbacks such as damage to the Chevron type seals during engagement with the stub as they are exposed to the sharp edge thereof and such as the one time operation of the lead seal type, among other things.